from manim import *



class math1(MovingCameraScene):
    def construct(self):
        self.camera.background_color = BLACK  # 设置背景颜色
        self.camera.frame_width = 100  # 设置边框宽度
        self.camera.frame_height = 60  # 设置边框高度
        self.camera.pixel_height = 1080  # 设置像素高度
        self.camera.pixel_width = 1920  # 设置像素宽度
        self.camera.center = ORIGIN  # 设置中心点位置
        self.camera.scale_factor = 1.0  # 设置缩放因子
        #设置横线
        for i in range(6*2+1):       
            dot1=Dot([-50,5*(i-6),0]).set_opacity(0.5)
            dot2=Dot([50,5*(i-6),0]).set_opacity(0.5)
            if i==6:
                line1=Line(dot1,dot2).set_color(WHITE).set_opacity(0.5)
                
            else:
                line1=Line(dot1,dot2).set_color(WHITE).set_opacity(0.5)
               
            self.add(dot1,dot2,line1)
        #设置竖线
        for i in range(10*2+1):        
            dot3=Dot([(i-10)*5,-30,0]).set_opacity(0.5)
            dot4=Dot([(i-10)*5,30,0]).set_opacity(0.5)
            if i==10:
                line2=Line(dot3,dot4).set_color(WHITE).set_opacity(0.5)
                
            else:
                line2=Line(dot3,dot4).set_color(WHITE).set_opacity(0.5)
            self.add(dot3,dot4,line2)
        #设置三个点
        dot1 = Dot(radius=1, color=RED)  
        dot1.move_to([-47.5,27.5,0]) 
        dot2 = Dot(radius=1, color=YELLOW)  
        dot2.move_to([-42.5,27.5,0])  
        dot3 = Dot(radius=1, color=GREEN)  
        dot3.move_to([-37.5,27.5,0])
        
        #镜头跟进效果 
        self.camera.frame.save_state()
        #题目出现
        text = Tex(r"\text{(张1000题1)设函数}$f\left( u,v\right) $\text{具有二阶连续偏导,函数}$g\left( x,y\right) =xy-f\left( \dfrac{y}{x},\dfrac{x}{y}\right) $\text{,求}"
                   ,tex_template=TexTemplateLibrary.ctex).scale(5.0).move_to([0,10,0])
        text1 = Tex(
                   r"$x^{2}\dfrac{\partial ^{2}g}{\partial x^{2}}+2xy\dfrac{\partial ^{2}g}{\partial x\partial y}+y^{2}\dfrac{\partial ^{2}g}{\partial y^{2}}$"
                   ,tex_template=TexTemplateLibrary.ctex).scale(5.0).move_to([-20,2,0])
         #题目出现
        text2 = Tex(r"\text{(张1000题2)设函数}$f\left( x,y\right) =\dfrac{x+y}{\left( 1+x^{2}\right) \left( 1+y^{2}\right) }\text{的极值} $"
                   ,tex_template=TexTemplateLibrary.ctex).scale(5.0).move_to([0,-10,0])
        text3 = Tex(r"\text{后记}",color=YELLOW
                   ,tex_template=TexTemplateLibrary.ctex).scale(20.0).move_to([0,25,0])

        self.play(Write(text),Write(text1),Write(text2),self.camera.frame.animate.scale(0.8))
        
        #镜头拉回
          #分析文本
        #text100=MarkupText("<b><i>分析/解：</i></b>",color=PINK).scale(5.0).move_to([-38,12.5,0])
        self.play(Restore(self.camera.frame))
        self.play(Write(text3))
        self.play(FadeIn(dot1),run_time=0.1)
        self.play(FadeIn(dot2),run_time=0.1)
        self.play(FadeIn(dot3),run_time=0.1)
       
        

        self.wait()
      